There is a NuGet package called "EikonDataAPI" at https://www.nuget.org/packages/EikonDataAPI/ . It's receiving 7 downloads per day and claims to be based on the same web interface as the Python Eikon Data API. However, it was last updated March 2018, the author is listed as "Active Help Service" rather than Eikon .NET SDK team, and I haven't seen .NET referenced anywhere as a language for accessing the Eikon Data API. Is this package supported?
This package is not an official product. This library is open-source, community-owned and not officially supported by Refinitiv.
It was mentioned in the developer portal at .NET Libraries for Eikon Data APIs Quick Start.
If there is an issue, it will be fixed by the community. It is similar to the R version available on GitHub.